In this paper, we present an original approach for enabling online reconfiguration of component-based applications. This research fits into our component composition methodology PacoSuite, that makes use of explicit connectors between components, called composition patterns. Both components and composition patterns are documented by making use of a special kind of MSC. We propose an algorithm to check whether a new component can fulfill the role of an old component in a given composition pattern, without the need to revalidate the entire composition all over again. To enable online reconfiguration, we extend the documentation of a component with a new primitive that specifies when a component reaches a safe state. This approach enables to swap a component at run-time, while maintaining a consistent application.